Effects of Temperature on Microstructure and Tribological Performance of a-CN_x Films Prepared by Pulsed Laser Deposition

Abstract

Amorphous carbon nitride (a-CN _x ) films were deposited onto silicon wafers at temperatures from RT up to 600°C by using pulsed laser deposition technique (PLD). The composition, morphology and microstructure of the CN _x films were characterized by X-ray photoelectron spectrum (XPS), scanning electron microscopy (SEM) and Raman spectrum. The tribological performance of the films was investigated using a ball-on-disk tribometer. With increasing the deposition temperature ranging from RT to 400°C, the N content of films dropped from 36 at% to 22 at%, the ratio of N-sp³ C bonds, hardness and friction coefficient of the film decreased. Further increase of deposition temperature led to the lack of nitrogen and the increasing degree of order in ringed sp² C˭C bonds of the amorphous carbon film. The mechanical and tribological performances became worse. The film deposited at 300°C showed a low friction coefficient of 0.11 and a preferable wear resistance of 1.65 × 10⁻⁷ mm³ N⁻¹ m⁻¹ in humid air.

Keywords:

• Carbon nitride film
• Friction and wear
• Microstructure
• Pulsed laser deposition

ACKNOWLEDGMENTS

The authors are grateful for the financial supports from National Natural Science Foundation of China (No. 50871102), Zhejiang Provincial Natural Science Foundation of China (No. Y406396), and a foundation of MOE Key Laboratory of Mechanical Manufacture and Automation of Zhejiang University of Technology.